The U.S. Supreme Court case Indiana v. Kentucky in 1896 was a dispute over the boundary line between the two states, specifically regarding an area of land known as Green River Island. The island had been considered part of Indiana's territory since its statehood in 1816 but shifted closer to Kentucky due to changes in the course of Ohio River, which serves as a natural border between them. In this case, Kentucky claimed ownership based on these geographical shifts and historical usage by its residents for farming and other purposes while Indiana argued that original jurisdiction should be maintained regardless of river movements. The court ruled in favor of Kentucky stating that when a river serving as a boundary changes gradually through natural processes (accretion), the boundary moves with it; however, if such change occurs suddenly (avulsion), then despite where water may flow afterwards, boundaries remain fixed at their former location unless otherwise agreed upon by involved parties or decided by Congress or courts. Since there was no evidence presented proving sudden shift occurred here - only gradual one - Green River Island became officially recognized as part of Kentucky.

In the dissenting opinion for Indiana v. Kentucky, Justice Harlan disagreed with the majority's decision to uphold a lower court ruling that favored Kentucky in a border dispute between the two states. He argued that historical evidence and past legal precedents supported Indiana's claim over an area of land located on the Ohio River. According to him, when Virginia ceded its western territory to create Kentucky, it did not include this disputed region; therefore, it should belong to Indiana based on previous treaties and agreements made during America’s early history. Furthermore, he believed that allowing Kentucky control over this area would disrupt established jurisdictions and potentially lead to future conflicts between these neighboring states.